The NEI Central Transgenic Animal Facility is a research support facility for all NEI intramural researchers requiring the use of transgenic mice in their research programs. We are currently providing transgenic animal support to researchers from six laboratories in the NEI (LI, LMDB, LMOD, LOT, LRCMB, OGCSB); in our program, there are currently 225 DNA constructs which are at various stages of completion. NEI researchers, using molecular biology techniques to study the eye, submit DNA constructs to our section for production of transgenic mice. We create transgenic mice by standard procedures, then biopsy and perform DNA analysis on the mice which are born from these procedures to identify transgene positive mice. At the researchers' request, we mate positive transgenic mice, wean litters, biopsy and analyze DNA from successive generations of transgenic mice, provide the transgenic animals to researchers for use in their experiments, and cryopreserve and bank embryos from important mouse lines (both transgenic and naturally occurring) for long term storage. We have recently begun collaborating on gene knockout projects, doing the ES cell injections into blastocysts. We also help researchers design transgenic projects and transgene/knockout vectors on a collaborative basis.This year we have: * accepted 10 new constructs for transgenic mouse production;* generated 56 transgenic founder mice; * set up 587 matings of transgenic mice; * weaned, tagged and tail biopsied 3,741 mice;* isolated DNA from 4,912 samples; performed 6,331 PCR analyses; * frozen 1191 embryos to preserve 3 mouse lines. Since the program began in 1991 we have: * accepted 225 transgene constructs * generated over 1,100 transgenic founder mice; * set up over 3,376 matings of transgenic mice; * weaned, tagged and tail biopsied over 31,900 mice;* isolated DNA from 34,100 samples; performed over 37,600 PCR analyses; * frozen approx. 6,990 embryos to preserve 23 mouse lines. * injected 8 ES cell lines into blastocysts for generation of chimeric mice.